DIAGNOSING
ACUTE PULMONARY EMBOLISM: EFFECT OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE ON
THE PERFORMANCE OF D-DIMER TESTING, VENTILATION/PERFUSION SCINTIGRAPHY, SPIRAL
COMPUTED TOMOGRAPHIC ANGIOGRAPHY, AND CONVENTIONAL ANGIOGRAPHY. ANTELOPE STUDY
GROUP. ADVANCES IN NEW TECHNOLOGIES EVALUATING THE LOCALIZATION OF PULMONARY
EMBOLISM.
Hartmann
IJ, et al. Am J Respir Crit Care Med 2000 Dec;162(6):2232-7.
BACKGROUND:
In patients with chronic obstructive pulmonary disease (COPD), differentiating
a pulmonary embolism (PE) from an exacerbation of COPD can be difficult, since
clinical signs and symptoms of the two conditions overlap. Development of
reliable noninvasive or minimally invasive techniques for the diagnosis of PE
is, especially in these patients, necessary.
DESIGN:
In this study we assessed the effect of COPD on the accuracy of the clinical
probability estimate (CPE), spiral computed tomographic angiography (SCTA),
D-dimer analysis, ventilation perfusion (V/Q) scintigraphy, and pulmonary
angiography for the diagnosis of PE. From May 1997 through March 1998, 627
consecutive patients with suspected PE were investigated in six teaching
hospitals. In these patients, D-dimer testing, CPE, V/Q scintigraphy, and SCTA
and/or pulmonary angiography were performed according to a strict diagnostic
protocol. The patients were also independently categorized as having COPD or
not.
RESULTS:
A diagnosis of COPD was established in 91 patients (15%). The prevalence of PE
was similar in patients with and without COPD (29% and 31%, respectively),
notwithstanding the larger proportion of nondiagnostic V/Q scan results in
patients with COPD (46% versus 21%, p < 0.001). The distribution of CPEs,
diagnostic value of the D-dimer assay and SCTA, and reproducibility of
pulmonary angiography were comparable among patients with and without COPD.
CONCLUSION:
The presence of COPD does not affect the diagnostic performance of CPE, D-dimer
testing, SCTA, or pulmonary angiography. Furthermore, although more
nondiagnostic V/Q scan results can be expected in the presence of COPD, V/Q
scintigraphy remains a valuable screening test in patients with COPD.
COMMENTS:
The v/Q scan has a higher likelihood of being nondiagnostic in patients with
COPD. One should consider a helical CT as the initial imaging study in those
patients with normal renal function.